1 /* 2 * Backlight Lowlevel Control Abstraction 3 * 4 * Copyright (C) 2003,2004 Hewlett-Packard Company 5 * 6 */ 7 8 #include <linux/module.h> 9 #include <linux/init.h> 10 #include <linux/device.h> 11 #include <linux/backlight.h> 12 #include <linux/notifier.h> 13 #include <linux/ctype.h> 14 #include <linux/err.h> 15 #include <linux/fb.h> 16 17 #ifdef CONFIG_PMAC_BACKLIGHT 18 #include <asm/backlight.h> 19 #endif 20 21 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ 22 defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) 23 /* This callback gets called when something important happens inside a 24 * framebuffer driver. We're looking if that important event is blanking, 25 * and if it is, we're switching backlight power as well ... 26 */ 27 static int fb_notifier_callback(struct notifier_block *self, 28 unsigned long event, void *data) 29 { 30 struct backlight_device *bd; 31 struct fb_event *evdata = data; 32 33 /* If we aren't interested in this event, skip it immediately ... */ 34 if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK) 35 return 0; 36 37 bd = container_of(self, struct backlight_device, fb_notif); 38 mutex_lock(&bd->ops_lock); 39 if (bd->ops) 40 if (!bd->ops->check_fb || 41 bd->ops->check_fb(evdata->info)) { 42 bd->props.fb_blank = *(int *)evdata->data; 43 backlight_update_status(bd); 44 } 45 mutex_unlock(&bd->ops_lock); 46 return 0; 47 } 48 49 static int backlight_register_fb(struct backlight_device *bd) 50 { 51 memset(&bd->fb_notif, 0, sizeof(bd->fb_notif)); 52 bd->fb_notif.notifier_call = fb_notifier_callback; 53 54 return fb_register_client(&bd->fb_notif); 55 } 56 57 static void backlight_unregister_fb(struct backlight_device *bd) 58 { 59 fb_unregister_client(&bd->fb_notif); 60 } 61 #else 62 static inline int backlight_register_fb(struct backlight_device *bd) 63 { 64 return 0; 65 } 66 67 static inline void backlight_unregister_fb(struct backlight_device *bd) 68 { 69 } 70 #endif /* CONFIG_FB */ 71 72 static ssize_t backlight_show_power(struct device *dev, 73 struct device_attribute *attr,char *buf) 74 { 75 struct backlight_device *bd = to_backlight_device(dev); 76 77 return sprintf(buf, "%d\n", bd->props.power); 78 } 79 80 static ssize_t backlight_store_power(struct device *dev, 81 struct device_attribute *attr, const char *buf, size_t count) 82 { 83 int rc = -ENXIO; 84 char *endp; 85 struct backlight_device *bd = to_backlight_device(dev); 86 int power = simple_strtoul(buf, &endp, 0); 87 size_t size = endp - buf; 88 89 if (*endp && isspace(*endp)) 90 size++; 91 if (size != count) 92 return -EINVAL; 93 94 mutex_lock(&bd->ops_lock); 95 if (bd->ops) { 96 pr_debug("backlight: set power to %d\n", power); 97 bd->props.power = power; 98 backlight_update_status(bd); 99 rc = count; 100 } 101 mutex_unlock(&bd->ops_lock); 102 103 return rc; 104 } 105 106 static ssize_t backlight_show_brightness(struct device *dev, 107 struct device_attribute *attr, char *buf) 108 { 109 struct backlight_device *bd = to_backlight_device(dev); 110 111 return sprintf(buf, "%d\n", bd->props.brightness); 112 } 113 114 static ssize_t backlight_store_brightness(struct device *dev, 115 struct device_attribute *attr, const char *buf, size_t count) 116 { 117 int rc = -ENXIO; 118 char *endp; 119 struct backlight_device *bd = to_backlight_device(dev); 120 int brightness = simple_strtoul(buf, &endp, 0); 121 size_t size = endp - buf; 122 123 if (*endp && isspace(*endp)) 124 size++; 125 if (size != count) 126 return -EINVAL; 127 128 mutex_lock(&bd->ops_lock); 129 if (bd->ops) { 130 if (brightness > bd->props.max_brightness) 131 rc = -EINVAL; 132 else { 133 pr_debug("backlight: set brightness to %d\n", 134 brightness); 135 bd->props.brightness = brightness; 136 backlight_update_status(bd); 137 rc = count; 138 } 139 } 140 mutex_unlock(&bd->ops_lock); 141 142 return rc; 143 } 144 145 static ssize_t backlight_show_max_brightness(struct device *dev, 146 struct device_attribute *attr, char *buf) 147 { 148 struct backlight_device *bd = to_backlight_device(dev); 149 150 return sprintf(buf, "%d\n", bd->props.max_brightness); 151 } 152 153 static ssize_t backlight_show_actual_brightness(struct device *dev, 154 struct device_attribute *attr, char *buf) 155 { 156 int rc = -ENXIO; 157 struct backlight_device *bd = to_backlight_device(dev); 158 159 mutex_lock(&bd->ops_lock); 160 if (bd->ops && bd->ops->get_brightness) 161 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd)); 162 mutex_unlock(&bd->ops_lock); 163 164 return rc; 165 } 166 167 static struct class *backlight_class; 168 169 static void bl_device_release(struct device *dev) 170 { 171 struct backlight_device *bd = to_backlight_device(dev); 172 kfree(bd); 173 } 174 175 static struct device_attribute bl_device_attributes[] = { 176 __ATTR(bl_power, 0644, backlight_show_power, backlight_store_power), 177 __ATTR(brightness, 0644, backlight_show_brightness, 178 backlight_store_brightness), 179 __ATTR(actual_brightness, 0444, backlight_show_actual_brightness, 180 NULL), 181 __ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL), 182 __ATTR_NULL, 183 }; 184 185 /** 186 * backlight_device_register - create and register a new object of 187 * backlight_device class. 188 * @name: the name of the new object(must be the same as the name of the 189 * respective framebuffer device). 190 * @devdata: an optional pointer to be stored for private driver use. The 191 * methods may retrieve it by using bl_get_data(bd). 192 * @ops: the backlight operations structure. 193 * 194 * Creates and registers new backlight device. Returns either an 195 * ERR_PTR() or a pointer to the newly allocated device. 196 */ 197 struct backlight_device *backlight_device_register(const char *name, 198 struct device *parent, void *devdata, struct backlight_ops *ops) 199 { 200 struct backlight_device *new_bd; 201 int rc; 202 203 pr_debug("backlight_device_register: name=%s\n", name); 204 205 new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL); 206 if (!new_bd) 207 return ERR_PTR(-ENOMEM); 208 209 mutex_init(&new_bd->update_lock); 210 mutex_init(&new_bd->ops_lock); 211 212 new_bd->dev.class = backlight_class; 213 new_bd->dev.parent = parent; 214 new_bd->dev.release = bl_device_release; 215 strlcpy(new_bd->dev.bus_id, name, BUS_ID_SIZE); 216 dev_set_drvdata(&new_bd->dev, devdata); 217 218 rc = device_register(&new_bd->dev); 219 if (rc) { 220 kfree(new_bd); 221 return ERR_PTR(rc); 222 } 223 224 rc = backlight_register_fb(new_bd); 225 if (rc) { 226 device_unregister(&new_bd->dev); 227 return ERR_PTR(rc); 228 } 229 230 new_bd->ops = ops; 231 232 #ifdef CONFIG_PMAC_BACKLIGHT 233 mutex_lock(&pmac_backlight_mutex); 234 if (!pmac_backlight) 235 pmac_backlight = new_bd; 236 mutex_unlock(&pmac_backlight_mutex); 237 #endif 238 239 return new_bd; 240 } 241 EXPORT_SYMBOL(backlight_device_register); 242 243 /** 244 * backlight_device_unregister - unregisters a backlight device object. 245 * @bd: the backlight device object to be unregistered and freed. 246 * 247 * Unregisters a previously registered via backlight_device_register object. 248 */ 249 void backlight_device_unregister(struct backlight_device *bd) 250 { 251 if (!bd) 252 return; 253 254 #ifdef CONFIG_PMAC_BACKLIGHT 255 mutex_lock(&pmac_backlight_mutex); 256 if (pmac_backlight == bd) 257 pmac_backlight = NULL; 258 mutex_unlock(&pmac_backlight_mutex); 259 #endif 260 mutex_lock(&bd->ops_lock); 261 bd->ops = NULL; 262 mutex_unlock(&bd->ops_lock); 263 264 backlight_unregister_fb(bd); 265 device_unregister(&bd->dev); 266 } 267 EXPORT_SYMBOL(backlight_device_unregister); 268 269 static void __exit backlight_class_exit(void) 270 { 271 class_destroy(backlight_class); 272 } 273 274 static int __init backlight_class_init(void) 275 { 276 backlight_class = class_create(THIS_MODULE, "backlight"); 277 if (IS_ERR(backlight_class)) { 278 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n", 279 PTR_ERR(backlight_class)); 280 return PTR_ERR(backlight_class); 281 } 282 283 backlight_class->dev_attrs = bl_device_attributes; 284 return 0; 285 } 286 287 /* 288 * if this is compiled into the kernel, we need to ensure that the 289 * class is registered before users of the class try to register lcd's 290 */ 291 postcore_initcall(backlight_class_init); 292 module_exit(backlight_class_exit); 293 294 MODULE_LICENSE("GPL"); 295 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 296 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction"); 297